The present invention salad oil which is a useful liquid oil from a specified oil or fat obtained by treating palm oil.
Solid fats which are in solid form at ambient temperature are usually converted into liquid oils to make the use thereof convenient. Solid oils such as palm oil are recently mass-produced and the quantity thereof will be increased in future. Therefore, development of new effective utilization of them is eagerly demanded. However, use of the solid fats per se is limited. Under these circumstances, it will be quite significant to produce a liquid salad oil from palm oil which is a solid fat.
Various processes were generally tried for liquefying solid fats. The most simple process comprises merely mixing a solid fat with a liquid oil. However, this process is not so effective, since the amount of the solid fat which can be incorporated into the liquid oil is limited to an extremely small amount in order to obtain the intended oil. This process is, therefore, not effective.
Another known process comprises fractionating a solid fat to take a low-melting point fraction, but it will be apparent from, for example, oleins obtained by fractionation of palm oil that even the low-melting point fraction tends to be in solid form in seasons other than summer and thus the product thus obtained is only a semi-liquid oil.
Under these circumstances, various processes based on transesterification reaction with lipase were recently proposed For example, Japanese Patent Unexamined Published Application (hereinafter referred to as "J. P. KOKAI") No. Sho 61-293389 discloses transesterification of palm oil and an odorless liquid starting oil with lipase, taking advantage of 1,3-specificity. However, this process is not always satisfactory, since the amount of palm oil which can be incorporated is only 50% at the most.
J. P. KOKAI Nos. Sho 49-107304 and 64-81899 describe a process wherein a liquid oil is incorporated into an oil obtained from palm oil by fractionation and transesterification of them is conducted. However, the obtained oil has an insufficient cooling resistance.